The increased prevalence of obesity among the children of military personnel has paralleled that observed in the civilian population. Disordered eating, especially binge or loss of control (LOC) eating, is common among adolescents and is a salient risk factor for obesity and the development of exacerbated disordered eating and depressive symptoms. The goal of this proposal is to test the effectiveness of interpersonal psychotherapy (IPT) to slow the trajectory of weight gain in adolescent boys and girls at high-risk for adult obesity by virtue of elevated body mass index (BMI) percentile and LOC eating. IPT targets the difficult social functioning and stressful events that are associated with LOC and highly relevant to the adolescent youth from military families. Male and female adolescent military dependents will be randomized to receive either the IPT weight gain prevention program or a health education (HE) control condition, for 12 weekly group sessions. Adolescents' weight status, eating behaviors, and mood will be assessed at baseline, immediately following the prevention program (12-weeks), and at 1-year follow-up. At 2-year and 3-year follow-up time points, participants' BMI and physiologic data will be collected via the Military Health System's electronic medical record system. It is hypothesized that adolescents who receive the IPT group program will show significantly less weight gain (or more weight loss) relative to those randomized to HE at 3-year follow-up. Additionally, it is hypothesized that adolescents receiving IPT (as compared to HE) will demonstrate improvements on secondary outcomes of interest, including the presence and frequency of classic binge eating episodes, as well as obesity-related physiological measures of health (e.g., fasting insulin). The overall goal of the proposal is to prevent excess weight gain and adult obesity, and to prevent worsening disordered eating and metabolic functioning among overweight military dependents at risk for adult obesity and binge eating disorders.